I think what they're getting at is the most common limiting factor for plant growth is almost never CO2. It's usually Nitrogen, or another two of the macro (P,K) or micronutrients.
Pretty much every agriculture advancement since the tractor and other machinery has been getting around the limiting factors of plant growth.
"Increasing CO2 has driven global greening: over the last 40 years, half of the world’s vegetated area has undergone greening, of which 70% is attributed to elevated CO2 (Zhu et al. 2016)"
Seems this whole thing got rather confused.